what is the correct timeing for a 75 1800/2000 (AP (serial)) motor. some books have it as 5 deg ATDC with strobe, mine has a decal for 7.5 BTDC. currently set at about 4 BTDC static. Non vacuum advance distributor. Tank of 50/50 pulp and ulp ,under load (trailer full of gravel)wants to self destruct.

As I understand it, this engine would have come out with a vacuum advance distributor, so the correct timing won't help you if you've got a centrifugal advance only distributor.

The best alternative (IMHO) would be to get a vacuum advance distributor. Failing that, set your centrifugal advance (009) distributor to 28 - 30 degrees advance at 3000 rpm.

7.5 IS IT!!!
THE atdc timing is for the US models with airpump & pollution equip etc

**SORRY , I did that in a hurry, I mean't to say 7.5 is the normal correct timing for a standard Kombi with vac advance, & without trailer load of gravel

[Edited on 6-3-2003 by kombikim]

thanks for that info. unfortunately most books are written for the american market.

When using the Bosch 009 distributor (no vacuum) then ALL VW engines must be set at 28-32 degrees at 3000+rpm for the bugs, and 28-30 degrees for the buses.


009s vary (cheap build) and the max advance is more important than the idle advance, so it must be set at 3000+rpm.

Once you've done that - if you prefer static timing you can measure the idle (or static) timing for THAT 009 and use it on THAT engine to set the timing in future.

I will probably be somewhere between 5 and 10BTDC (009s vary - remember).

As others have said, the 5ATDC setting were never used in Aus - only on double vacuum distributors in the US market.

Use as much of the 28-30 as you can without the engine pinging/detonating. If it still detonates at 28, don't go lower or the engine will be underadvanced at higher rpm and run hotter than it needs to - if it still pings at 28 degrees, use a higher octane fuel.

Your engine SHOULD run on normal unleaded if it has stock compression and reasonable jetting in the carbs. High compression or lean running needs a higher octane fuel to prevent detonation with the higher heat.

But if it pings on unleaded - use unbleaded premium, or even BP Ultimate/Shell Optimax/Mobil synergy8000 if it still pings.

put the strobe on it today and it was set at 28 deg. hasn't detonated since so maybe only under extreme load ?